1. Field of the Invention
The present invention relates to a logic card comprising a printed circuitboard equipped with electrical modules, a plug connector part having a multitude of contact elements and a contact pressure component, for example, a cooling device which exerts pressure against a surface of a printed circuitboard.
2. Description of the Prior Art
When constructing large electronic systems such as, for example, data processing systems, it is desirable to obtain signal lines which are as short as possible and which have a defined characteristic impedance and, therefore, to achieve high switching speeds. This can be achieved with the assistance of logic cards which exhibit single-layer or multi-layer printed circuitboards having integrated modules and which are connected to a motherboard by way of electrical plugtype connectors. In order to achieve a high conductor density, the motherboard is likewise constructed multi-layer and contains signal lines for connecting components to one another, but also contains potential and supply lines. Given logic cards having maximum packing density, the numerous external terminals required for that purpose are distributed over a smallest space on the underside in order to produce the connections to the printed circuitboard without indirect routes. Known from U.S. Pat. No. 3,993,123, is a logic card having heat-emitting modules which are contacted at one side to a carrier plate. The modules lie beneath a cooling device which surrounds the modules like a cap and proceeding from which one or more resilient parts press a heat-dissipating element against each module. The pressure generated is diverted to the edges of the plate which are flanged to the cooling device, whereby, however, the carrier can experience sag.
Since a large number of vertically-projecting plug pins is also secured to the carrier plate, a sag complicates plug-in and pulling of the logic card, this, as known, requiring pins which are aligned exactly parallel relative to one another. Otherwise, the danger exists that pins will be bent or broken off and, as a result thereof, that faulty connections will arise or that, at the very least, even greater plug-in and pulling forces will be required than would otherwise be necessary anyway because of the large number of connections. Moreover, the danger exists, given a printed circuitboard yielding to a mechanical stress, that fine cracks will arise in the affected conductor paths and will interrupt the connections. This situation is all the more likely to occur when the pins are rigidly connected to the printed circuitboard and the already-existing excursion, given frequent change of the logic card, is increased, on the one hand, by pulling forces and, on the other hand, is restored due to the elasticity of the printed circuitboard, this potentially leading to fatigue of the conductor path material.